>Psychtoolbox>PsychGamma

y=MonitorGamma(x,x0,gamma)

This function is commonly used to describe the “gamma” function of a video
monitor. x represents input voltage and y represents luminance. There are two
parameters: threshold x0, and the exponent gamma. In my applications, x and y
have been normalized so that the gamma curve always goes through (0,0) and (1,1),
so I’ve built that constraint into the function:
if x<=x0 then y=0
if x>x0 then y=((x-x0)/(1-x0))^gamma
The arguments can be scalars or matrices; MonitorGamma will do the right thing.
Note that it is unreasonable for x0 to be outside the unit interval, or for g to
be negative, but these constraints are not enforced here.

See MonitorGammaError.

Denis Pelli 5/28/96